This project is designed to provide information on the mechanisms operating within reflex systems which include alpha motoneurons as the output link, as well as on the interconnection and interaction of different reflex systems. Particular consideration is given to correlations between synaptic organization, intrinsic neuronal properties, dynamic behavior and the physiological characteristics of the muscle fibers innervated by the motoneurons studies. BIBLIOGRAPHIC REFERENCES: Burke, R.E.: The effect of stimulation rate and pattern on synaptic transmission in the mammalian central nervous system. In Reswick, J.B. and Hambrecht, F.T. (Eds.): Functional Electrical Stimulation - Applications in Neural Prostheses. New York, Marcel Dekker, In press, 1977. Kanda, K., Burke, R.E. and Walmsley, B.: Differential control of fast and slow twitch motor units in the decerebrate cat. Exp. Brain Res. In press, 1977.